Access network selection for a ue not supporting nas over non-3gpp access

ABSTRACT

Apparatuses, methods, and systems are disclosed for access network selection for UEs not supporting NAS over non-3GPP access. One apparatus includes a processor and a transceiver for communicating with one or more non-3GPP access networks. The processor creates a first list of available PLMNs, each PLMN connectable via a non-3GPP access network without using a NAS protocol. The processor selects a first PLMN from the first list and selects a first network slice supported by the first PLMN. Here, the first network slice is identified by a first S-NSSAI. The processor creates a second list of available non-3GPP access networks and selects a first non-3GPP access network from the second list. The processor begins a connectivity procedure over the first non-3GPP access network. Here, the connectivity procedure creates a data connection for the apparatus via the first network slice in the first PLMN, and the connectivity procedure does not use the NAS protocol.

FIELD

The subject matter disclosed herein relates generally to wirelesscommunications and more particularly relates to access network selectionfor UEs not supporting NAS over non-3GPP access.

BACKGROUND

The following abbreviations and acronyms are herewith defined, at leastsome of which are referred to within the following description.

Third Generation Partnership Project (“3GPP”), Fifth-Generation Core(“5GC”),

Access and Mobility Management Function (“AMF”), Access NetworkPerformance (“ANP”), Access Point Name (“APN”), Access Stratum (“AS”),Carrier Aggregation (“CA”), Clear Channel Assessment (“CCA”), ControlChannel Element (“CCE”), Channel State Information (“CSI”), CommonSearch Space (“CSS”), Data Network Name (“DNN”), Data Radio Bearer(“DRB”), Downlink Control Information (“DCI”), Downlink (“DL”), EnhancedClear Channel Assessment (“eCCA”), Enhanced Mobile Broadband (“eMBB”),Evolved Node-B (“eNB”), Evolved Packet Core (“EPC”), Evolved UMTSTerrestrial Radio Access Network (“E-UTRAN”), EuropeanTelecommunications Standards Institute (“ETSI”), Fixed Access GatewayFunction (“FAGF”), Fixed Network Residential Gateway (“FN-RG”), FrameBased Equipment (“FBE”), Frequency Division Duplex (“FDD”), FrequencyDivision Multiple Access (“FDMA”), Globally Unique Temporary UE Identity(“GUTI”), Hybrid Automatic Repeat Request (“HARQ”), Home SubscriberServer (“HSS”), Internet-of-Things (“IoT”), Key Performance Indicators(“KPI”), Licensed Assisted Access (“LAA”), Load Based Equipment (“LBE”),Listen-Before-Talk (“LBT”), Long Term Evolution (“LTE”), LTE Advanced(“LTE-A”), Medium Access Control (“MAC”), Multiple Access (“MA”),Modulation Coding Scheme (“MCS”), Machine Type Communication (“MTC”),Massive MTC (“mMTC”), Mobility Management (“MM”), Mobility ManagementEntity (“MME”), Multiple Input Multiple Output (“MIMO”), Multipath TCP(“MPTCP”), Multi User Shared Access (“MUSA”), Non-Access Stratum(“NAS”), Narrowband (“NB”), Network Function (“NF”), Network AccessIdentifier (“NAI”), Next Generation (e.g., 5G) Node-B (“gNB”), NextGeneration Radio Access Network (“NG-RAN”), New Radio (“NR”), PolicyControl & Charging (“PCC”), Policy Control Function (“PCF”), PolicyControl and Charging Rules Function (“PCRF”), Packet Data Network(“PDN”), Packet Data Unit (“PDU”), PDN Gateway (“PGW”), Public LandMobile Network (“PLMN”), Quality of Service (“QoS”), Quadrature PhaseShift Keying (“QPSK”), Registration Area (“RA”), Radio Access Network(“RAN”), Radio Access Technology (“RAT”), Radio Resource Control(“RRC”), Receive (“RX”), Single Network Slice Selection AssistanceInformation (“S-NSSAI”), Scheduling Request (“SR”), Secure User PlaneLocation (“SUPL”), Serving Gateway (“SGW”), Session Management Function(“SMF”), System Information Block (“SIB”), Tracking Area (“TA”),Transport Block (“TB”), Transport Block Size (“TBS”), Time-DivisionDuplex (“TDD”), Time Division Multiplex (“TDM”), Transmission andReception Point (“TRP”), Transmit (“TX”), Trusted WLAN InterworkingFunction (“TWIF”), Uplink Control Information (“UCI”), Unified DataManagement (“UDM”), User Entity/Equipment (Mobile Terminal) (“UE”),Uplink (“UL”), User Plane (“UP”), Universal Mobile TelecommunicationsSystem (“UMTS”), Ultra-reliability and Low-latency Communications(“URLLC”), UE Route Selection Policy (“URSP”), and Wireless Local AreaNetwork (“WLAN”), Wireless Local Area Network Selection Policy(“WLANSP”), Worldwide Interoperability for Microwave Access (“WiMAX”).

In fifth generation (“5G”) wireless communication systems, a non-3GPPaccess network (notably, a WLAN) may support interfaces with mobilenetworks (PLMNs) in order to enable wireless devices (UEs) to connect tothese mobile networks and utilize their services. For example, a WLANaccess network may support the N2 interface and the N3 interface(3GPP-defined 5GC interfaces) with a PLMN for connecting wirelessdevices to the 5G core (5GC) network in this PLMN via WLAN access.However, not every UE supports NAS over non-3GPP access.

BRIEF SUMMARY

Methods for access network selection for UEs not supporting NAS overnon-3GPP access are disclosed. Apparatuses and systems also perform thefunctions of the methods.

One method (e.g., performed by a UE) for access network selection forUEs not supporting NAS over non-3GPP access includes creating a firstlist of available PLMNs, each PLMN connectable via a non-3GPP accessnetwork without using a NAS protocol. The method includes selecting afirst PLMN from the first list and selecting a first network slicesupported by the first PLMN. Here, the first network slice is identifiedby a S-NSSAI. The method includes creating a second list of availablenon-3GPP access networks and selecting a first non-3GPP access networkfrom the second list. The method includes beginning a connectivityprocedure over the first non-3GPP access network. Here, the connectivityprocedure creates a data connection for the apparatus via the firstnetwork slice in the first PLMN. Moreover, the connectivity proceduredoes not use the NAS protocol.

Another method (e.g., performed by a non-3GPP access point) for accessnetwork selection for UEs not supporting NAS over non-3GPP accessincludes receiving, from one or more interworking functions, a set ofPLMNs for which connectivity is supported without using a non-accessstratum NAS protocol. Here, the one or more interworking functionsprovide access to one or more PLMNs. The method includes receiving, foreach PLMN in the set, a list of one or more supported network slices, anetwork slice being identified by a S-NSSAI. The method includesreceiving, from a first remote unit, a connection request message, theconnection request message indicating a first PLMN from the set and afirst S-NSSAI. The method includes forwarding the connection requestmessage to a first interworking function.

BRIEF DESCRIPTION OF THE DRAWINGS

A more particular description of the embodiments briefly described abovewill be rendered by reference to specific embodiments that areillustrated in the appended drawings. Understanding that these drawingsdepict only some embodiments and are not therefore to be considered tobe limiting of scope, the embodiments will be described and explainedwith additional specificity and detail through the use of theaccompanying drawings, in which:

FIG. 1 is a schematic block diagram illustrating one embodiment of awireless communication system for access network selection for UEs notsupporting NAS over non-3GPP access;

FIG. 2A is a block diagram illustrating one embodiment of a networkarchitecture for access network selection for UEs not supporting NASover non-3GPP access;

FIG. 2B is a diagram illustrating one example of network lists foraccess network selection for UEs not supporting NAS over non-3GPPaccess;

FIG. 3 is a block diagram illustrating one embodiment of a networkarchitecture for access network selection for UEs not supporting NASover non-3GPP access;

FIG. 4 is a block diagram illustrating another embodiment of a networkarchitecture for access network selection for UEs not supporting NASover non-3GPP access;

FIG. 5 is a schematic block diagram illustrating one embodiment of auser equipment apparatus for access network selection for UEs notsupporting NAS over non-3GPP access;

FIG. 6 is a schematic block diagram illustrating one embodiment of anetwork equipment apparatus for access network selection for UEs notsupporting NAS over non-3GPP access;

FIG. 7A is a block diagram illustrating one embodiment of a networkprocedure for access network selection for UEs not supporting NAS overnon-3GPP access;

FIG. 7B is a continuation of the network procedure of FIG. 6A;

FIG. 8 is a flow chart diagram illustrating one embodiment of a firstmethod for access network selection for UEs not supporting NAS overnon-3GPP access; and

FIG. 9 is a flow chart diagram illustrating one embodiment of a secondmethod for access network selection for UEs not supporting NAS overnon-3GPP access.

DETAILED DESCRIPTION

As will be appreciated by one skilled in the art, aspects of theembodiments may be embodied as a system, apparatus, method, or programproduct. Accordingly, embodiments may take the form of an entirelyhardware embodiment, an entirely software embodiment (includingfirmware, resident software, micro-code, etc.) or an embodimentcombining software and hardware aspects.

For example, the disclosed embodiments may be implemented as a hardwarecircuit comprising custom very-large-scale integration (“VLSI”) circuitsor gate arrays, off-the-shelf semiconductors such as logic chips,transistors, or other discrete components. The disclosed embodiments mayalso be implemented in programmable hardware devices such as fieldprogrammable gate arrays, programmable array logic, programmable logicdevices, or the like. As another example, the disclosed embodiments mayinclude one or more physical or logical blocks of executable code whichmay, for instance, be organized as an object, procedure, or function.

Furthermore, embodiments may take the form of a program product embodiedin one or more computer readable storage devices storing machinereadable code, computer readable code, and/or program code, referredhereafter as code. The storage devices may be tangible, non-transitory,and/or non-transmission. The storage devices may not embody signals. Ina certain embodiment, the storage devices only employ signals foraccessing code.

Any combination of one or more computer readable medium may be utilized.The computer readable medium may be a computer readable storage medium.The computer readable storage medium may be a storage device storing thecode. The storage device may be, for example, but not limited to, anelectronic, magnetic, optical, electromagnetic, infrared, holographic,micromechanical, or semiconductor system, apparatus, or device, or anysuitable combination of the foregoing.

More specific examples (a non-exhaustive list) of the storage devicewould include the following: an electrical connection having one or morewires, a portable computer diskette, a hard disk, a random-access memory(“RAM”), a read-only memory (“ROM”), an erasable programmable read-onlymemory (“EPROM” or Flash memory), a portable compact disc read-onlymemory (“CD-ROM”), an optical storage device, a magnetic storage device,or any suitable combination of the foregoing. In the context of thisdocument, a computer readable storage medium may be any tangible mediumthat can contain, or store, a program for use by or in connection withan instruction execution system, apparatus, or device.

Reference throughout this specification to “one embodiment,” “anembodiment,” or similar language means that a particular feature,structure, or characteristic described in connection with the embodimentis included in at least one embodiment. Thus, appearances of the phrases“in one embodiment,” “in an embodiment,” and similar language throughoutthis specification may, but do not necessarily, all refer to the sameembodiment, but mean “one or more but not all embodiments” unlessexpressly specified otherwise. The terms “including,” “comprising,”“having,” and variations thereof mean “including but not limited to,”unless expressly specified otherwise. An enumerated listing of itemsdoes not imply that any or all of the items are mutually exclusive,unless expressly specified otherwise. The terms “a,” “an,” and “the”also refer to “one or more” unless expressly specified otherwise.

Furthermore, the described features, structures, or characteristics ofthe embodiments may be combined in any suitable manner. In the followingdescription, numerous specific details are provided, such as examples ofprogramming, software modules, user selections, network transactions,database queries, database structures, hardware modules, hardwarecircuits, hardware chips, etc., to provide a thorough understanding ofembodiments. One skilled in the relevant art will recognize, however,that embodiments may be practiced without one or more of the specificdetails, or with other methods, components, materials, and so forth. Inother instances, well-known structures, materials, or operations are notshown or described in detail to avoid obscuring aspects of anembodiment.

Aspects of the embodiments are described below with reference toschematic flowchart diagrams and/or schematic block diagrams of methods,apparatuses, systems, and program products according to embodiments. Itwill be understood that each block of the schematic flowchart diagramsand/or schematic block diagrams, and combinations of blocks in theschematic flowchart diagrams and/or schematic block diagrams, can beimplemented by code. This code may be provided to a processor of ageneral-purpose computer, special purpose computer, or otherprogrammable data processing apparatus to produce a machine, such thatthe instructions, which execute via the processor of the computer orother programmable data processing apparatus, create means forimplementing the functions/acts specified in the schematic flowchartdiagrams and/or schematic block diagrams.

The code may also be stored in a storage device that can direct acomputer, other programmable data processing apparatus, or other devicesto function in a particular manner, such that the instructions stored inthe storage device produce an article of manufacture includinginstructions which implement the function/act specified in the schematicflowchart diagrams and/or schematic block diagrams.

The code may also be loaded onto a computer, other programmable dataprocessing apparatus, or other devices to cause a series of operationalsteps to be performed on the computer, other programmable apparatus, orother devices to produce a computer implemented process such that thecode which execute on the computer or other programmable apparatusprovide processes for implementing the functions/acts specified in theschematic flowchart diagrams and/or schematic block diagram.

The schematic flowchart diagrams and/or schematic block diagrams in theFigures illustrate the architecture, functionality, and operation ofpossible implementations of apparatuses, systems, methods, and programproducts according to various embodiments. In this regard, each block inthe schematic flowchart diagrams and/or schematic block diagrams mayrepresent a module, segment, or portion of code, which includes one ormore executable instructions of the code for implementing the specifiedlogical function(s).

It should also be noted that, in some alternative implementations, thefunctions noted in the block may occur out of the order noted in theFigures. For example, two blocks shown in succession may, in fact, beexecuted substantially concurrently, or the blocks may sometimes beexecuted in the reverse order, depending upon the functionalityinvolved. Other steps and methods may be conceived that are equivalentin function, logic, or effect to one or more blocks, or portionsthereof, of the illustrated Figures.

The description of elements in each figure may refer to elements ofproceeding figures. Like numbers refer to like elements in all figures,including alternate embodiments of like elements.

Methods, apparatuses, and systems are disclosed for access networkselection for UEs not supporting NAS over non-3GPP access. As mentionedabove, a non-3GPP access network (e.g., a WLAN) may support interfaceswith mobile networks (e.g., one or more PLMNs) in order to enablewireless devices to connect to these mobile networks and utilize theirservices. Note that 5GC networks support the Non-Access Stratum (NAS)protocol for access control, connection management and sessionmanagement. Thus, all UEs must support the NAS protocol in order toconnect to 5GC, either via 3GPP access (e.g. NG-RAN), or via non-3GPPaccess (e.g. WLAN). The N1 interfaces in 5G carry NAS messages betweenthe UE and 5GC. However, there is currently a large number of UEs(including laptops, IoT devices, etc.) which do not support the NASprotocol over non-3GPP access, but they may want to establishconnectivity via 5GC.

When a wireless device wants to establish a data connection via a 5GCvia a non-3GPP access network, but does not support the NAS protocolover non-3GPP access, the wireless device requires a method forselecting (a) the PLMN to connect to via non-3GPP access, (b) a slicetype (an S-NSSAI) to use in the selected PLMN, and (c) a non-3GPP accessnetwork that can provide connectivity to the selected PLMN and to theselected slice type.

FIG. 1 depicts a wireless communication system 100 for access networkselection for UEs not supporting NAS over non-3GPP access, according toembodiments of the disclosure. In one embodiment, the wirelesscommunication system 100 includes at least one remote unit 105, a 5G-RAN115, and a mobile core network 140. The 5G-RAN 115 and the mobile corenetwork form a mobile communication network. The 5G-RAN 115 may becomposed of a 3GPP access network 120 containing at least one cellularbase unit 121and/or a non-3GPP access network 130 containing at leastone access point 131. The remote unit communicates with the 3GPP accessnetwork 120 using 3GPP communication links 123 and communicates with thenon-3GPP access network 130 using non-3GPP communication links 133. Eventhough a specific number of remote units 105, 3GPP access networks 120,cellular base units 121, 3GPP communication links 123, non-3GPP accessnetworks 130, access points 131, non-3GPP communication links 133, andmobile core networks 140 are depicted in FIG. 1, one of skill in the artwill recognize that any number of remote units 105, 3GPP access networks120, cellular base units 121, 3GPP communication links 123, non-3GPPaccess networks 130, access points 131, non-3GPP communication links133, and mobile core networks 140 may be included in the wirelesscommunication system 100.

In one implementation, the wireless communication system 100 iscompliant with the 5G system specified in the 3GPP specifications. Moregenerally, however, the wireless communication system 100 may implementsome other open or proprietary communication network, for example, LTEor WiMAX, among other networks. The present disclosure is not intendedto be limited to the implementation of any particular wirelesscommunication system architecture or protocol.

In one embodiment, the remote units 105 may include computing devices,such as desktop computers, laptop computers, personal digital assistants(“PDAs”), tablet computers, smart phones, smart televisions (e.g.,televisions connected to the Internet), smart appliances (e.g.,appliances connected to the Internet), set-top boxes, game consoles,security systems (including security cameras), vehicle on-boardcomputers, network devices (e.g., routers, switches, modems), or thelike. In some embodiments, the remote units 105 include wearabledevices, such as smart watches, fitness bands, optical head-mounteddisplays, or the like. Moreover, the remote units 105 may be referred toas UEs, subscriber units, mobiles, mobile stations, users, terminals,mobile terminals, fixed terminals, subscriber stations, user terminals,wireless transmit/receive unit (“WTRU”), a device, or by otherterminology used in the art.

The remote units 105 may communicate directly with one or more of thecellular base units 121 in the 3GPP access network 120 via uplink (“UL”)and downlink (“DL”) communication signals. Furthermore, the UL and DLcommunication signals may be carried over the 3GPP communication links123. Similarly, the remote units 105 may communicate with one or moreaccess points 131 in the non-3GPP access network(s) 130 via UL and DLcommunication signals carried over the non-3GPP communication links 133.Here, the access networks 120 and 130 are intermediate networks thatprovide the remote units 105 with access to the mobile core network 140.

In some embodiments, the remote units 105 communicate with a remote host155 via a network connection with the mobile core network 140. Forexample, an application 107 (e.g., web browser, media client,telephone/VoIP application) in a remote unit 105 may trigger the remoteunit 105 to establish a PDU session (or other data connection) with themobile core network 140 using the 5G-RAN 115 (e.g., a 3GPP accessnetwork 120 and/or a non-3GPP access network 130). The mobile corenetwork 140 then relays traffic between the remote unit 105 and eitherthe first data network 150 or the second data network 152 using the PDUsession. Note that the remote unit 105 may establish one or more PDUsessions (or other data connections) with the mobile core network 140.As such, the remote unit 105 may have at least one PDU session forcommunicating with the first data network 150 and at least one PDUsession for communicating with the second data network 152.

The cellular base units 121 may be distributed over a geographic region.In certain embodiments, a cellular base unit 121 may also be referred toas an access terminal, a base, a base station, a Node-B, an eNB, a gNB,a Home Node-B, a relay node, a device, or by any other terminology usedin the art. The cellular base units 121 are generally part of a radioaccess network (“RAN”), such as the 3GPP access network 120, that mayinclude one or more controllers communicably coupled to one or morecorresponding cellular base units 121. These and other elements of radioaccess network are not illustrated but are well known generally by thosehaving ordinary skill in the art. The cellular base units 121 connect tothe mobile core network 140 via the 3GPP access network 120.

The cellular base units 121 may serve a number of remote units 105within a serving area, for example, a cell or a cell sector, via a 3GPPcommunication link 123. The cellular base units 121 may communicatedirectly with one or more of the remote units 105 via communicationsignals. Generally, the cellular base units 121 transmit DLcommunication signals to serve the remote units 105 in the time,frequency, and/or spatial domain. Furthermore, the DL communicationsignals may be carried over the 3GPP communication links 123. The 3GPPcommunication links 123 may be any suitable carrier in licensed orunlicensed radio spectrum. The 3GPP communication links 123 facilitatecommunication between one or more of the remote units 105 and/or one ormore of the cellular base units 121.

The non-3GPP access networks 130 may be distributed over a geographicregion. Each non-3GPP access network 130 may serve a number of remoteunits 105 with a serving area. Typically, a serving area of the non-3GPPaccess network 130 is smaller than the serving area of a cellular baseunit 121. An access point 131 in a non-3GPP access network 130 maycommunicate directly with one or more remote units 105 by receiving ULcommunication signals and transmitting DL communication signals to servethe remote units 105 in the time, frequency, and/or spatial domain. BothDL and UL communication signals are carried over the non-3GPPcommunication links 133. The 3GPP communication links 123 and non-3GPPcommunication links 133 may employ different frequencies and/ordifferent communication protocols. In various embodiments, an accesspoint 131 may communicate using unlicensed radio spectrum. The mobilecore network 140 may provide services to a remote unit 105 via thenon-3GPP access networks 130, as described in greater detail herein.

In some embodiments, a non-3GPP access network 130 connects to themobile core network 140 via an interworking function 135. Theinterworking function 135 provides interworking between the remote unit105 and the mobile core network 140. Here, the interworking function 135implements the NAS protocol and exchanges NAS messages with the mobilecore network 140 on behalf of the remote unit 105. The interworkingfunction 135 supports connectivity via the “N1 ” (for NAS messageexchange), “N2”, and “N3” interfaces. As depicted, both the 3GPP accessnetwork 120 and the interworking function 135 communicate with the AMF142 using a “N2” interface. The interworking function 135 alsocommunicates with the first UPF 141 using a “N3” interface, while the3GPP access network 120 communicates with the second UPF 143 using a“N3” interface.

The non-3GPP access network 130 may support three different types ofinterworking functions 135. A first type (“Type 1”) supportsconnectivity to one or more 5GC networks for UEs which do not supportthe NAS protocol. A second type (“Type 2”) supports connectivity to oneor more 5GC networks for UEs which do support the NAS protocol. A thirdtype (“Type 3”) supports connectivity to one or more EPC networks usingthe existing S2a procedures (see 3GPP TS 23.402). Note that a non-3GPPaccess network 130 may support one, two, or all three types ofinterworking functions. The different types of interworking functionsare discussed in greater detail below, with reference to FIG. 2.

In certain embodiments, a non-3GPP access network 130 may be controlledby an operator of the mobile core network 140 and may have direct accessto the mobile core network 140. Such a non-3GPP AN deployment isreferred to as a “trusted non-3GPP access network.” A non-3GPP accessnetwork 130 is considered as “trusted” when it is operated by the 3GPPoperator, or a trusted partner, and supports certain security features,such as strong air-interface encryption.

In contrast, a non-3GPP AN deployment that is not controlled by anoperator (or trusted partner) of the mobile core network 140, does nothave direct access to the mobile core network 140, or does not supportthe certain security features is referred to as a “non-trusted” non-3GPPaccess network.

In one embodiment, the mobile core network 140 is a 5G core (“5GC”) orthe evolved packet core (“EPC”), which may be coupled to a data networks150 and 152, like the Internet and private data networks, among otherdata networks. A remote unit 105 may have a subscription or otheraccount with the mobile core network 140. Each mobile core network 140belongs to a single public land mobile network (“PLMN”). The presentdisclosure is not intended to be limited to the implementation of anyparticular wireless communication system architecture or protocol.

The mobile core network 140 includes several network functions (“NFs”).As depicted, the mobile core network 140 includes multiple user planefunctions (“UPFs”). Here, the mobile core network 140 includes at leasta first UPF (“UPF-1”) 141 and a second UPF (“UPF-2”) 143. In thedepicted embodiment, the first UPF 141 serves the non-3GPP accessnetwork 130 and the second UPF 143 serves the 3GPP access network 120.In other embodiments, the UPF 141 (or UPF 143) may serve both the 3GPPaccess network 120 and the non-3GPP access network 130.

The mobile core network 140 also includes multiple control planefunctions including, but not limited to, an Access and MobilityManagement Function (“AMF”) 142 that serves both the 3GPP access network120 and the non-3GPP access network 130, a Session Management Function(“SMF”) 145, and a Policy Control Function (“PCF”) 147. In certainembodiments, the mobile core network 140 may also include anAuthentication Server Function (“AUSF”), a Unified Data Managementfunction (“UDM”), a Network Repository Function (“NRF”) 146 (used by thevarious NFs to discover and communicate with each other over APIs), orother NFs defined for the SGC.

Although specific numbers and types of network functions are depicted inFIG. 1, one of skill in the art will recognize that any number and typeof network functions may be included in the mobile core network 140.Moreover, where the mobile core network 140 is an EPC, the depictednetwork functions may be replaced with appropriate EPC entities, such asan MME, S-GW, P-GW, HSS, and the like.

As depicted, a remote unit 105 (e.g., a UE) may connect to the mobilecore network (e.g., to a 5G mobile communication network) via two typesof accesses: (1) via 3GPP access network 120 and (2) via a non-3GPPaccess network 130. The first type of access (e.g., 3GPP access network120) uses a 3GPP-defined type of wireless communication (e.g., NG-RAN)and the second type of access (e.g., non-3GPP access network 130) uses anon-3GPP-defined type of wireless communication (e.g., WLAN). The 5G-RAN115 refers to any type of 5G access network that can provide access tothe mobile core network 140, including the 3GPP access network 120 andthe non-3GPP access network 130.

In various embodiments, the mobile core network 140 supports differenttypes of mobile data connections and different types of network slices,wherein each mobile data connection utilizes a specific network slice.The different network slices are not shown in FIG. 1 for ease ofillustration, but their support is assumed.

As described in greater detail below, the remote unit 105 may determineto establish a data connection via the mobile core network 140 and via anon-3GPP access network 130. For example, the decision to establish adata connection via the mobile core network 140 may be triggered by theapplication 107 requesting to establish a PDU session to the first datanetwork 150 and where policy in the remote unit indicates that this PDUsession should preferably be established over non-3GPP access. However,if the remote unit 105 does not support the NAS protocol over non-3GPPaccess, then the remote unit 105 requires the aid of an interworkingfunction 135. As discussed above, the remote unit 105 must select 1) aPLMN (e.g., a mobile core network 140) to connect to via non-3GPPaccess, 2) a network slice (e.g., S-NSSAI) to use in the selected PLMN,and 3) a non-3GPP access network that can provide connectivity to theselected PLMN and to the selected slice type.

In some embodiments, the remote unit 105 determines whether to use atrusted non-3GPP access network or an untrusted non-3GPP access network.Such a decision may be made based on capabilities of the remote unit 105and connectivity capabilities of the discovers non-3GPP access networks130. In response to deciding to use a trusted non-3GPP access network,the remote unit 105 determine a non-3GPP access network 130 and a typeof connectivity to use to connect to the mobile core network 140.

FIG. 2A depicts a network architecture 200 for access network selectionfor UEs not supporting NAS over non-3GPP access, according toembodiments of the disclosure. The network architecture 200 includes aUE 205 which does not support the NAS protocol over non-3GPP access andwants to establish a data connection to the data network (“DN”) 250 overa non-3GPP access network and via a 5G core (5GC) network in a PLMN.

In one example, the UE 205 may want to establish a data connection toIMS in order to utilize IMS-based multimedia services, e.g. videocalling. In another example, the UE 205 may want to establish a dataconnection to the MMS servers of a mobile operator in order to send andreceive MMS messages. In yet another example, the UE 205 may simply wantto establish a data connection to the Internet via a 5GC in order tobenefit from the enhanced connectivity services offers by the 5Goperator, e.g. anti-virus protection, malware detection, contentcompression, etc. In all these examples, the UE 205 must have asubscription with a 5G PLMN (the Home PLMN of the UE 205) and thenecessary access credentials.

The N1 interfaces shown in FIG. 2 carry NAS messages between the UE 205and 5GC in the first PLMN 230, via NG-RAN 210. As noted above, there iscurrently a large number of UEs (including laptops, IoT devices, etc.)which do not support the NAS protocol over non-3GPP access but, yet,they may want to establish connectivity via 5GC, e.g. to utilize5GC-based services, such as IMS multimedia services, optimized IoTconnectivity services, etc. In order to enable UEs which do not supportthe NAS protocol over non-3GPP access to establish connectivity via 5Gcore networks, the non-3GPP access network must support an InterworkingApparatus, which implements the NAS protocol and exchanges NAS messageswith the 5GC on behalf of the UE. In FIG. 2, this Interworking Apparatusis the Interworking Apparatus Type 1, which supports an N1 interfacetoward 5GC (for NAS message exchange), in addition to the regular N2 andN3 interfaces.

As shown in FIG. 2, a non-3GPP access network may support threedifferent types of Interworking Apparatuses:

Type 1: Each Interworking Apparatus Type 1 supports connectivity to oneor more 5GC networks for UEs which do not support the NAS protocol. Anexample for such Interworking Apparatus is the Trusted WLAN InterworkingFunction (“TWIF”) and the Fixed Network Residential Gateway (“FN-RG”).

Type 2: Each Interworking Apparatus Type 2 supports connectivity to oneor more 5GC networks for UEs which do support the NAS protocol overnon-3GPP access and the applicable NAS procedures. An example of suchInterworking Apparatus is the Trusted Non-3GPP Gateway Function(“TNGF”).

Type 3: Each Interworking Apparatus Type 3 supports connectivity to oneor more EPC networks for UEs which support the applicable S2aconnectivity procedures and protocols. An example of such InterworkingApparatus is the Trusted WLAN Access Gateway (“TWAG”).

For establishing a data connection with a DN, the UE 205 needs (a) toselect a 5G PLMN network, (b) to select a slice type to be used in theselected 5G PLMN, and (b) to select a non-3GPP access network that canprovide “5G connectivity-without-NAS” to the selected slice type in theselected 5G PLMN (recall that the UE 205 does not support NAS overnon-3GPP access). The UE 205 makes these selections by executing an“access network selection” procedure, e.g., as described herein. Afterthe access network selection procedure is executed, the UE 205 initiatesa connectivity procedure over the selected non-3GPP access network.During this connectivity procedure, the UE 205 is authenticated by itsHome PLMN, it is authorized to connect to the selected non-3GPP accessnetwork and to the selected 5G PLMN, and a data connection 255 via thenon-3GPP access network and the 5G PLMN is established that connects theUE 205 with the Data Network 250. This data connection 255 goes throughthe selected slice type in the selected 5G PLMN.

In the depicted scenario, the UE 205 has discovered three non-3GPPaccess networks 215-225. The first non-3GPP access network 215 isidentified by SSID ‘x1’ and contains all three types of interworkingapparatuses. The second non-3GPP access network 220 is identified bySSID ‘x2’ and contains interworking apparatuses of the first and thirdtypes. The third non-3GPP access network 225 is identified by SSID ‘x3’and contains interworking apparatuses of the first and second types.

The network architecture 200 includes four PLMNs: a first PLMN(“PLMN-a”) 230, a second PLMN (“PLMN-b”) 235, a third PLMN (“PLMN-c”)240, and a fourth PLMN (“PLMN-d”) 245. The first PLMN 230 includes a 5GCand an EPC. Note that the first PLMN 230 interworks with the firstnon-3GPP access network 215 using “5G connectivity-without-NAS,” “5Gconnectivity,” and “S2a connectivity.” The second PLMN 235 includes anEPC. Note that the second PLMN 235 interworks with the first non-3GPPaccess network 215 using “S2a connectivity” and with the second non-3GPPaccess network 220 using “S2a connectivity.”

The third PLMN 240 includes an EPC. Note that the third PLMN 240interworks with the second non-3GPP access network 220 using “S2aconnectivity.” The fourth PLMN 245 includes a SGC. Note that the fourthPLMN 245 interworks with the second non-3GPP access network 220 using“5G connectivity-without-NAS” and interworks with the third non-3GPPaccess network 225 using “5G connectivity-without-NAS” and “5Gconnectivity.”

The non-3GPP access networks 215-225 advertise information about the3GPP networks (PLMNs) they interwork with, e.g., by using the ANQPprotocol. Note that each non-3GPP access network may support “S2aconnectivity,” “5G connectivity” and/or “5G connectivity-without-NAS” toone or more PLMNs. To connect to a PLMN using a non-3GPP access network,the UE 205 needs to select (a) a non-3GPP access network, (b) a PLMN,and (c) a connectivity type, i.e. “S2a connectivity”, “5G connectivity,”or “5G connectivity-without-NAS”. If the UE 205 does not support NASover no-3GPP access, then the UE 205 is unable to use interworkingapparatuses of the second and third types. Selection procedures for a UEthat does support NAS over non-3GPP access are discussed in PCTapplication PCT/EP2018/077364 titled “Selecting a non-3GPP accessnetwork,” which is incorporated by reference.

Each non-3GPP access network may advertise one or more of: a PLMNList-1, a PLMN List-2, a PLMN List-3, and a PLMN List-4. A PLMN List-1includes those PLMNs with which “AAA connectivity” is supported. Anon-3GPP access network supports “AAA connectivity” with a PLMN when itdeploys an AAA function that can connect with a 3GPP AAA Server/Proxy inthis PLMN, via an STa interface (trusted WLAN to EPC), or via a SWainterface (untrusted WLAN to EPC).

A PLMN List-2 includes PLMNs with which “S2a connectivity” is supported.A non-3GPP access network supports “S2a connectivity” with a PLMN whenit deploys an interworking apparatus that can connect with a PGW in thisPLMN, via an S2a interface (e.g., deploys a Type 3 interworkingfunction).

A PLMN List-3 includes PLMNs with which “5G connectivity” is supported.A non-3GPP access network supports “5G connectivity” with a PLMN when itdeploys a TNGF function that can connect with an AMF function and an UPFfunction in this PLMN via N2 and N3 interfaces, respectively (e.g.,deploys a Type 2 interworking function).

A PLMN List-4 includes PLMNs with which “5G connectivity-without-NAS” issupported. A non-3GPP access network supports “5Gconnectivity-without-NAS” with a PLMN when it deploys an interworkingfunction that can connect with an AMF function in this PLMN via N1 andN2 interfaces and with an UPF function in this PLMN via N3 interface(e.g., deploys a Type 1 interworking function).

In some embodiments, the UE 205 sends an ANQP query to a non-3GPP accessnetwork requesting “3GPP Cellular Network” information. In response, thenon-3GPP access network replies with an ANQP response having a “3GPPCellular Network” information element that contains the PLMN List-1, thePLMN List-2, the PLMN List-3 and/or the PLMN List-4. Note that the PLMNList-3 and PLMN List-4 may be used to indicate interworking with 5GPLMNs.

The UE 205 determines if a non-3GPP access network supports “5Gconnectivity-without-NAS” to a given PLMN by receiving the PLMN List-4advertised by this non-3GPP access network. For a given PLMN, if thisPLMN is not included in the PLMN List-4 advertised by a non-3GPP accessnetwork, then the non-3GPP access network does not support “5Gconnectivity-without-NAS.”

In the depicted embodiment, the first non-3GPP access network 215advertises a PLMN List-1 of “PLMN-a, PLMN-b,” a PLMN List-2 of “PLMN-a,PLMN-b,” a PLMN List-3 of “PLMN-a” and a PLMN List-3 of “PLMN-a.” Thesecond non-3GPP access network 220 advertises a PLMN List-1 of “PLMN-b,PLMN-c,” a PLMN List-2 of “PLMN-b, PLMN-c,” and a PLMN List-4 of“PLMN-d.” The third non-3GPP access network 225 advertises a PLMN List-3of “PLMN-d” and a PLMN List-4 of “PLMN-d.”

FIG. 2B depicts one embodiment of the UE 205 generating a list ofavailable non-3GPP access networks 260 and a list of available PLMNs265, according to embodiments of the disclosure. From the PLMN Lists-1,PLMN Lists-2, PLMN Lists-3, and PLMN Lists-4 advertised by the non-3GPPaccess networks 215-225, the UE 205 creates a list of available non-3GPPaccess networks 260. As depicted, the list of available non-3GPP accessnetworks 260 includes identifiers for the available non-3GPP accessnetworks 215-225 (e.g., SSIDs). For each available non-3GPP accessnetwork, the list of available non-3GPP access networks 260 indicatesthose PLMNs for which the WLAN supports trusted connectivity as well asthe types of connectivity supported (e.g., S2a connectivity, 5Gconnectivity, and/or 5G connectivity-without-NAS).

From the information in the list of available non-3GPP access networks260, the UE 205 may create a list of available PLMNs 265. Here, the listof available PLMNs 265 indicates the available PLMNs and the types oftrusted connectivity supported (e.g., S2a connectivity, 5G connectivity,and/or 5G connectivity-without-NAS). From this, the UE 205 may derive alist 270 of available PLMNs connectable via a non-3GPP access networkwithout using a NAS protocol.

FIG. 3 depicts a first system architecture 300 including a WLANsupporting 5G connectivity-without-NAS. FIG. 3 shows a more detailedsystem architecture for the case where the non-3GPP access network is aWLAN access network. The first system architecture 300 may be oneembodiment of the network architecture 200. For ease of illustration,only two 5G PLMNs are shown: a first 5GC (“5GC-a”) 330 and a second 5GC(“5GC-b”) 335. Each 5GC belongs to a PLMN, for example the first PLMN230 and the fourth PLMN 245. As depicted, the first 5GC 330 includes afirst AMF (“AMF-1”) 340, a second AMF (“AMF-2”) 345, a first SMF(“SMF-1”) 355, and a first UPF (“UPF-1”) 365. As depicted, the second5GC 335 includes a third AMF (“AMF-3”) 350, a second SMF (“SMF-2”) 360,and a second UPF (“UPF-2”) 370.

The first system architecture 300 includes a WLAN access network 305that considered a “trusted” WLAN access network from the PLMNs point ofview, because it directly interfaces with these PLMNs via the standardN1, N2 and N3 interfaces. The WLAN access network 305 includes a firstTWAP (“TWAP-1”) 310 and a second TWAP (“TWAP-2”) 315. The TWAPs (TrustedWLAN Access Points) are similar to a regular WLAN access point. The WLANaccess network 305 includes a first TWIF (“TWIF-1”) 320 and a secondTWIF (“TWIF-2”) 325. The TWIFs (Trusted WLAN Interworking Function) areembodiments of the Interworking Apparatus Type 1.

FIG. 4 depicts a second system architecture 400 including a fixedbroadband access network supporting 5G connectivity-without-NAS. FIG. 4shows a more detailed system architecture for the case where thenon-3GPP access network is a fixed broadband access network. The secondsystem architecture 400 may be one embodiment of the networkarchitecture 200. For ease of illustration, only two 5G PLMNs are shown:the first 5GC (“5GC-a”) 330 and the second 5GC (“5GC-b”) 335.

The second system architecture 400 includes a fixed broadband accessnetwork 405 that directly interfaces with these PLMNs via the standardN1, N2 and N3 interfaces. The fixed broadband access network 405includes a first FN-RG (“FN-RG-1”) 410 and a second FN-RG (“FN-RG-2”)415. The FN-RGs (Fixed Network Residential Gateway) are residentialgateways providing Ethernet or WLAN access to UEs. The fixed broadbandaccess network 405 includes a first FAGF (“FAGF-1”) 420 and a secondFAGF (“FAGF-2”) 425. The FAGFs (Fixed Access Gateway Function) areembodiments of the Interworking Apparatus Type 1.

FIG. 5 depicts one embodiment of a user equipment apparatus 500 that maybe used for access network selection for UEs not supporting NAS overnon-3GPP access, according to embodiments of the disclosure. The userequipment apparatus 500 may be one embodiment of the remote unit 105.Furthermore, the user equipment apparatus 500 may include a processor505, a memory 510, an input device 515, an output device 520, atransceiver 525. In some embodiments, the input device 515 and theoutput device 520 are combined into a single device, such as a touchscreen. In certain embodiments, the user equipment apparatus 500 doesnot include any input device 515 and/or output device 520.

As depicted, the transceiver 525 includes at least one transmitter 530and at least one receiver 535. Here, the transceiver 525 communicateswith one or more non-3GPP access networks. Additionally, the transceiver525 may support at least one network interface 540. Here, the at leastone network interface 540 facilitates communication with an eNB or gNB(e.g., using the “Uu” interface). Additionally, the at least one networkinterface 540 may include an interface used for communications with anUPF, an SMF, and/or a P-CSCF.

The processor 505, in one embodiment, may include any known controllercapable of executing computer-readable instructions and/or capable ofperforming logical operations. For example, the processor 505 may be amicrocontroller, a microprocessor, a central processing unit (“CPU”), agraphics processing unit (“GPU”), an auxiliary processing unit, a fieldprogrammable gate array (“FPGA”), or similar programmable controller. Insome embodiments, the processor 505 executes instructions stored in thememory 510 to perform the methods and routines described herein. Theprocessor 505 is communicatively coupled to the memory 510, the inputdevice 515, the output device 520, the first transceiver 525, and thesecond transceiver 530.

In a first implementation, the processor 505 creates a first list ofavailable PLMNs, each PLMN connectable via a non-3GPP access networkwithout using a NAS protocol (e.g., as depicted in the list 270). Theprocessor 505 selects a first PLMN from the first list and selects afirst network slice supported by the first PLMN. Here, the first networkslice is identified by a first S-NSSAI. The processor 505 creates asecond list of available non-3GPP access networks (e.g., connectable tothe first PLMN and first network slice) and selects a first non-3GPPaccess network from the second list. The processor 505 then controls thetransceiver 525 to begin a connectivity procedure over the firstnon-3GPP access network. Here, the connectivity procedure creates a dataconnection for the apparatus via the first network slice in the firstPLMN. Moreover, the connectivity procedure does not use the NASprotocol.

In some embodiments, the processor 505 creates the first list ofavailable PLMNs by discovering a plurality of available non-3GPP accessnetworks and determining, for each available non-3GPP access network, aset of PLMNs which are connectable without using the NAS protocol andone or more network slices supported by each PLMN in the set. In certainembodiments, determining the set of PLMNs which are connectable withoutusing the NAS protocol and the one or more network slices supported byeach PLMN in the set includes using an access network query protocol toacquire a list of PLMNs connectable via each available non-3GPP accessnetwork without using the NAS protocol and the network slices supportedfor each PLMN in the list of PLMNs connectable via each availablenon-3GPP access network without using the NAS protocol.

In certain embodiments, the first non-3GPP access network is a highestpriority available non-3GPP access network that supports connectivity tothe first network slice in the first PLMN. In some embodiments, theprocessor 505 selects the first S-NSSAI using configuration informationin the apparatus. In some embodiments, creating the second list includesdiscovering a plurality of available non-3GPP access networks andordering the plurality of available non-3GPP access networks into aprioritized list based on a set of WLANSP rules. In such embodiments,the second list may be ordered based on operating parameters of theplurality of available non-3GPP access networks.

In some embodiments, beginning the connectivity procedure over the firstnon-3GPP access network includes sending a request message to the firstnon-3GPP access network that indicates the first PLMN and the firstS-NSSAI. In certain embodiments, the request message includes NAIcontaining identifiers for the first PLMN and for the first S-NSSAI. Incertain embodiments, beginning the connectivity procedure includescreating a data connection via the first network slice in the first PLMNand via one of: a TWIF in the first non-3GPP access network, and a FN-RGin the first non-3GPP access network.

The memory 510, in one embodiment, is a computer readable storagemedium. In some embodiments, the memory 510 includes volatile computerstorage media. For example, the memory 510 may include a RAM, includingdynamic RAM (“DRAM”), synchronous dynamic RAM (“SDRAM”), and/or staticRAM (“SRAM”). In some embodiments, the memory 510 includes non-volatilecomputer storage media. For example, the memory 510 may include a harddisk drive, a flash memory, or any other suitable non-volatile computerstorage device. In some embodiments, the memory 510 includes bothvolatile and non-volatile computer storage media. In some embodiments,the memory 510 stores data relating to access network selection, forexample storing lists of available non-3GPP access networks, lists ofavailable PLMNs, priority rules, and the like. In certain embodiments,the memory 510 also stores program code and related data, such as anoperating system (“OS”) or other controller algorithms operating on theuser equipment apparatus 500 and one or more software applications.

The input device 515, in one embodiment, may include any known computerinput device including a touch panel, a button, a keyboard, a stylus, amicrophone, or the like. In some embodiments, the input device 515 maybe integrated with the output device 520, for example, as a touchscreenor similar touch-sensitive display. In some embodiments, the inputdevice 515 includes a touchscreen such that text may be input using avirtual keyboard displayed on the touchscreen and/or by handwriting onthe touchscreen. In some embodiments, the input device 515 includes twoor more different devices, such as a keyboard and a touch panel.

The output device 520, in one embodiment, may include any knownelectronically controllable display or display device. The output device520 may be designed to output visual, audible, and/or haptic signals. Insome embodiments, the output device 520 includes an electronic displaycapable of outputting visual data to a user. For example, the outputdevice 520 may include, but is not limited to, an LCD display, an LEDdisplay, an OLED display, a projector, or similar display device capableof outputting images, text, or the like to a user. As another,non-limiting, example, the output device 520 may include a wearabledisplay such as a smart watch, smart glasses, a heads-up display, or thelike. Further, the output device 520 may be a component of a smartphone, a personal digital assistant, a television, a table computer, anotebook (laptop) computer, a personal computer, a vehicle dashboard, orthe like.

In certain embodiments, the output device 520 includes one or morespeakers for producing sound. For example, the output device 520 mayproduce an audible alert or notification (e.g., a beep or chime). Insome embodiments, the output device 520 includes one or more hapticdevices for producing vibrations, motion, or other haptic feedback. Insome embodiments, all or portions of the output device 520 may beintegrated with the input device 515. For example, the input device 515and output device 520 may form a touchscreen or similar touch-sensitivedisplay. In other embodiments, all or portions of the output device 520may be located near the input device 515.

As discussed above, the transceiver 525 communicates with one or morenetwork functions of a mobile communication network via one or moreaccess networks. The transceiver 525 operates under the control of theprocessor 505 to transmit messages, data, and other signals and also toreceive messages, data, and other signals. For example, the processor505 may selectively activate the transceiver (or portions thereof) atparticular times in order to send and receive messages. The transceiver525 may include one or more transmitters 530 and one or more receivers535. In certain embodiments, the one or more transmitters 530 and/or theone or more receivers 535 may share transceiver hardware and/orcircuitry. For example, the one or more transmitters 530 and/or the oneor more receivers 535 may share antenna(s), antenna tuner(s),amplifier(s), filter(s), oscillator(s), mixer(s),modulator/demodulator(s), power supply, and the like.

In various embodiments, the transceiver 525 is configured tocommunication with 3GPP access network(s) 120 and the non-3GPP accessnetwork(s) 130. In some embodiments, the transceiver 525 implementsmodem functionality for the 3GPP access network(s) 120 and/or thenon-3GPP access network(s) 130. In one embodiment, the transceiver 525implements multiple logical transceivers using different communicationprotocols or protocol stacks, while using common physical hardware.

FIG. 6 depicts one embodiment of a network equipment apparatus 600 thatmay be used for access network selection for UEs not supporting NAS overnon-3GPP access, according to embodiments of the disclosure. The networkequipment apparatus 600 may be one embodiment of the remote unit 105.Furthermore, network equipment apparatus 600 may include a processor605, a memory 610, an input device 615, an output device 620, atransceiver 625. In some embodiments, the input device 615 and theoutput device 620 are combined into a single device, such as a touchscreen. In certain embodiments, the network equipment apparatus 600 doesnot include any input device 615 and/or output device 620.

As depicted, the transceiver 625 includes at least one transmitter 630and at least one receiver 635. Here, the transceiver 625 communicateswith one or more remote units 105 and with one or more interworkingfunctions 135 that provide access to one or more PLMNs Additionally, thetransceiver 625 may support at least one network interface 640. Here,the at least one network interface 640 facilitates communication with anAMF (e.g., using the “N1” and/or “N2” interface). Additionally, the atleast one network interface 640 may include an interface used forcommunications with an UPF, an SMF, and/or a P-CSCF.

The processor 605, in one embodiment, may include any known controllercapable of executing computer-readable instructions and/or capable ofperforming logical operations. For example, the processor 605 may be amicrocontroller, a microprocessor, a central processing unit (“CPU”), agraphics processing unit (“GPU”), an auxiliary processing unit, a fieldprogrammable gate array (“FPGA”), or similar programmable controller. Insome embodiments, the processor 605 executes instructions stored in thememory 610 to perform the methods and routines described herein. Theprocessor 605 is communicatively coupled to the memory 610, the inputdevice 615, the output device 620, the first transceiver 625, and thesecond transceiver 630.

In a first implementation, the processor 605 receives, from one or moreinterworking functions, a set of PLMNs for which connectivity issupported without using a NAS protocol. The processor 605 receives, foreach PLMN in the set, a list of one or more supported network slices, anetwork slice being identified by a S-NSSAI. The processor 605 receives,from a first remote unit, a connection request message, the connectionrequest message indicating a first PLMN from the set and a firstS-NSSAI. The processor 605 controls the transceiver 625 to forward theconnection request message to a first interworking function.

In some embodiments, the processor 605 further selects the firstinterworking function based on the first PLMN and the first S-NSSAI. Incertain embodiments, the connection request message includes a NAIcontaining identifiers for the first PLMN and for the first S-NS SAI.

The memory 610, in one embodiment, is a computer readable storagemedium. In some embodiments, the memory 610 includes volatile computerstorage media. For example, the memory 610 may include a RAM, includingdynamic RAM (“DRAM”), synchronous dynamic RAM (“SDRAM”), and/or staticRAM (“SRAM”). In some embodiments, the memory 610 includes non-volatilecomputer storage media. For example, the memory 610 may include a harddisk drive, a flash memory, or any other suitable non-volatile computerstorage device. In some embodiments, the memory 610 includes bothvolatile and non-volatile computer storage media. In some embodiments,the memory 610 stores data relating to access network selection, forexample storing lists of available PLMNs, priority rules, and the like.In certain embodiments, the memory 610 also stores program code andrelated data, such as an operating system (“OS”) or other controlleralgorithms operating on the network equipment apparatus 600 and one ormore software applications.

The input device 615, in one embodiment, may include any known computerinput device including a touch panel, a button, a keyboard, a stylus, amicrophone, or the like. In some embodiments, the input device 615 maybe integrated with the output device 620, for example, as a touchscreenor similar touch-sensitive display. In some embodiments, the inputdevice 615 includes a touchscreen such that text may be input using avirtual keyboard displayed on the touchscreen and/or by handwriting onthe touchscreen. In some embodiments, the input device 615 includes twoor more different devices, such as a keyboard and a touch panel.

The output device 620, in one embodiment, may include any knownelectronically controllable display or display device. The output device620 may be designed to output visual, audible, and/or haptic signals. Insome embodiments, the output device 620 includes an electronic displaycapable of outputting visual data to a user. For example, the outputdevice 620 may include, but is not limited to, an LCD display, an LEDdisplay, an OLED display, a projector, or similar display device capableof outputting images, text, or the like to a user. As another,non-limiting, example, the output device 620 may include a wearabledisplay such as a smart watch, smart glasses, a heads-up display, or thelike. Further, the output device 620 may be a component of a smartphone, a personal digital assistant, a television, a table computer, anotebook (laptop) computer, a personal computer, a vehicle dashboard, orthe like.

In certain embodiments, the output device 620 includes one or morespeakers for producing sound. For example, the output device 620 mayproduce an audible alert or notification (e.g., a beep or chime). Insome embodiments, the output device 620 includes one or more hapticdevices for producing vibrations, motion, or other haptic feedback. Insome embodiments, all or portions of the output device 620 may beintegrated with the input device 615. For example, the input device 615and output device 620 may form a touchscreen or similar touch-sensitivedisplay. In other embodiments, all or portions of the output device 620may be located near the input device 615.

As discussed above, the transceiver 625 communicates with one or moreremote units and with one or more interworking functions that provideaccess to one or more PLMNs. The transceiver 625 operates under thecontrol of the processor 605 to transmit messages, data, and othersignals and also to receive messages, data, and other signals. Forexample, the processor 605 may selectively activate the transceiver (orportions thereof) at particular times in order to send and receivemessages. The transceiver 625 may include one or more transmitters 630and one or more receivers 635. In certain embodiments, the one or moretransmitters 630 and/or the one or more receivers 635 may sharetransceiver hardware and/or circuitry. For example, the one or moretransmitters 630 and/or the one or more receivers 635 may shareantenna(s), antenna tuner(s), amplifier(s), filter(s), oscillator(s),mixer(s), modulator/demodulator(s), power supply, and the like.

In various embodiments, the transceiver 625 is configured tocommunication with 3GPP access network(s) 120 and the non-3GPP accessnetwork(s) 130. In some embodiments, the transceiver 625 implementsmodem functionality for the 3GPP access network(s) 120 and/or thenon-3GPP access network(s) 130. In one embodiment, the transceiver 625implements multiple logical transceivers using different communicationprotocols or protocol stacks, while using common physical hardware.

FIGS. 7A-7B depicts an access network selection procedure 700 for accessnetwork selection for UEs not supporting NAS over non-3GPP access,according to embodiments of the disclosure. The access network selectionprocedure 700 involves the UE 205, which does not support the NASprotocol over non-3GPP access, and wants to establish a data connectionto a data network (e.g. IMS) via a 5G PLMN and via a non-3GPP accessnetwork. As aforementioned, the UE 205 executes the access networkselection procedure 700 in order to (a) select a 5G PLMN network, (b)select a slice type to be used in the selected 5G PLMN, and (b) select anon-3GPP access network that can provide 5G connectivity-without-NAS tothe selected slice type in the selected 5G PLMN.

The access network selection procedure 700 further involves a WLANaccess network 702, an example of a non-3GPP access network, and a 5Gcore network 330, an example of a 5GC in a PLMN. Note that the WLANaccess network 702 includes a TWAP 704 and a TWIF 706. The WLAN accessnetwork 702 may be one embodiment of the non-3GPP access network 130and/or WLAN access network 305, discussed above. As such, the TWAP 704may be one embodiment of the access point 131 and the TWIF 706 may beone embodiment of the interworking function 135. While FIGS. 7A-7B showone TWIF, there may be multiple TWIFs in the same WLAN access network,as shown in FIG. 3. Also, while FIGS. 7A-7B show only one 5G PLMNavailable via the TWIF 706, the same TWIF may support interworking withmultiple 5G PLMNs.

The access network selection procedure 700 begins in Step 1 as the TWIF706 (e.g., each TWIF in the WLAN access network 702) registers with the5GC network 330 (e.g., in PLMN-a) using its own credentials (see block718). This registration uses NAS signaling between the TWIF 706 and anAMF 708 in the 5GC network 330. In the Registration Accept messagereceived by the TWIF 706 there is a list of “allowed S-NSSAIs”, whichindicates the S-NSSAIs (network slice types) in the 5GC network 330 thatthe TWIF 706 is allowed to use. This means that the TWIF 706 may requesta data connection (e.g., a PDU Session) using any of the allowedS-NSSAIs. Note that the AMF 708 may receive a “default DNN for delegatedPDU session’ and a “default S-NSSAI for delegated PDU sessions.”

In Step 2, the TWIF 706 indicates to the TWAP 704 (and to any other TWAPit can communicate with) that it supports 5G connectivity-without-NAS toPLMN-a and to the list of “allowed S-NSSAIs” in PLMN-a (see messaging720). The TWAP 704 may receive similar indications from all other TWIFsit can communicate with. After this step, the TWAP 704 knows the PLMNswith which it can provide 5G connectivity-without-NAS and the S-NSSAIs(slice types) in each one of these PLMNs.

Note that the steps 1-2 shown here are not part of the access networkselection procedure executed by the UE 205, but may be used in order toindicate to TWAP 704 the 5G PLMNs and the slice types (S-NSSAIs) in each5G PLMN which are supported by each TWIF 706.

In Step 4, the UE 205 discovers information about each availablenon-3GPP access network (including the WLAN access network 702), whereinthe information includes operating parameters (e.g. BSS load, backhaulbandwidth, etc.) and a list of supported PLMNs 724 (see messaging 722).Additionally, each PLMN may optionally be associated with a connectivitytype. In one example, this information is discovered by sending an ANQPQuery to every available TWAP 704 and receiving an ANQP Response,wherein the response includes the operating parameters and the list ofsupported PLMNs (see block 726). The list of supported PLMNs 724 caninclude four different types of lists, each one associated with adifferent connectivity type:

PLMN List-1: It includes the PLMNs with which the TWAP can support AAAconnectivity. This type of connectivity can be used for authenticatingUEs by a PLMN in this list and for authorizing UEs access to thenon-3GPP access network by a PLMN in this list.

PLMN List-2: It includes the PLMNs with which the TWAP can support S2aconnectivity. This type of connectivity allows UEs to connect to an EPCnetwork in one of the PLMNs in this list.

PLMN List-3: It includes the PLMNs with which the TWAP can support 5Gconnectivity. This type of connectivity allows UEs to connect to a 5GCnetwork in one of the PLMNs in this list.

PLMN List-4: It includes the PLMNs with which the TWAP can support 5Gconnectivity-without-NAS. This type of connectivity allows UEs, which donot support NAS over non-3GPP access, to establish a data connectionthrough a 5GC network in one of the PLMNs in this list. In addition, foreach PLMN in the PLMN List-4, one or more supported S-NSSAIs may beincluded, as discussed above. A TWAP learns the PLMNs with which 5Gconnectivity-without-NAS is supported, as well as the S-NSSAIs supportedby each of these PLMNs in step 2, i.e. after receiving this informationfrom one or more TWIF.

In the example scenario shown in FIG. 2, the UE may discover thefollowing information:

For the first non-3GPP access network 215, the operating parameters maybe: BSS load=30%, SSID=x1. Also, non-3GPP access network 1 supports 5Gconnectivity-without-NAS with PLMN-a (and, optionally, indicates networkslices S-NSSAI-x and S-NSSIA-y).

For the second non-3GPP access network 220, the operating parameters maybe: Backhaul DL speed=10 Mbps, Backhaul DL load=75%, SSID=x2. Also,non-3GPP access network 2 supports 5G connectivity-without-NAS withPLMN-s (and, optionally, indicates network slice S-NSSAI-z).

For the third non-3GPP access network 225, the operating parameters maybe: SSID=x3. Also, non-3GPP access network 3 supports 5Gconnectivity-without-NAS with PLMN-d (and, optionally, indicates networkslice S-NSSAI-w).

In Step 5, the UE 205 creates a first list of PLMNs that contains allPLMNs with which 5G connectivity-without-NAS is supported (see block728). Essentially, this list contains the PLMNs included in the PLMNList-4 received by all available TWAPs. In the example scenario shown inFIG. 2, the first list of PLMNs includes PLMN-a and PLMN-d.

In Step 6, the UE 205 selects a first PLMN from the first list of PLMNsand also a first S-NSSAI from the S-NSSAIs supported by the first PLMN(see block 730). In the example scenario shown in FIG. 2, the UE 205 mayselect PLMN-d and one of the supported S-NSSAIs (either S-NSSAI-z orS-NSSAI-w). The first PLMN may be selected as follows: If the UE isconnected to a PLMN via 3GPP access and this PLMN is included in thelist of available PLMNs, the UE selects this PLMN. However, if the UE isconnected to a PLMN via 3GPP access and this this PLMN is not includedin the list of available PLMNs, but it is included in the “Non-3GPPaccess node selection information”, then the UE 205 selects this PLMNand executes the Combined ePDG/N3IWF Selection procedure.

Otherwise, if the UE 205 is not connected to a PLMN via 3GPP access, orif the UE 205 is connected to a PLMN via 3GPP access but this PLMN isneither in the list of available PLMNs nor in the “Non-3GPP access nodeselection information”, then the UE 205 determines if it is in its homeregion/country or not. If the UE 205 determines to be located in itshome region/country, then the UE 205 selects the home PLMN (“HPLMN”), ifincluded in the list of available PLMNs. If not included in the list ofavailable PLMNs, then the UE 205 selects an equivalent HPLMN(“E-HPLMN”), if an E-HPLMN is included in the list of available PLMNs.In certain embodiments, if the list of available PLMNs does not includethe HPLMN and does not include an E-HPLMN, then the UE 205 stops theprocedure and may attempt to connect via untrusted non-3GPP access.

If the UE 205 determines to be located in a visited region/country, thenthe UE 205 determines if it is mandatory to select a PLMN in the visitedregion/country. Determining if it is mandatory to select a PLMN in thevisited region/country may include the following: if the UE 205 has IPconnectivity (e.g., the UE 205 is connected via 3GPP access), the UE 205sends a DNS query and receives a DNS response that indicates if a PLMNmust be selected in the visited region/country. The DNS responseincludes a lifetime that denotes how long the DNS response can becached. In certain embodiments, the FQDN in the DNS query will bedifferent from the DNS query used for ePDG/N3IWF selection. Also, theDNS response does not need to include a list of PLMNs that support “S2aconnectivity” and/or “5G connectivity” because the UE 205 has the listof available PLMNs. Otherwise, if the UE 205 has no IP connectivity(e.g., the UE 205 is not connected via 3GPP access), then the UE 205 mayuse a cached DNS response that was received in the past, or may uselocal configuration that indicates which visited countries mandate aPLMN selection in the visited region/country.

If the UE 205 determines that it is not mandatory to select a PLMN inthe visited region/country, and the HPLMN or an E-HPLMN is included inthe list of available PLMNs, then the UE 205 selects the HPLMN or anE-HPLMN, whichever is included in the list of available PLMNs.Otherwise, the UE 205 selects a PLMN in the visited region/country byconsidering, in priority order, the PLMNs in the Operator ControlledPLMN Selector list (in USIM). The UE 205 selects the highest priorityPLMN in the Operator Controlled PLMN Selector list that is also includedin the list of available PLMNs. Note that if the list of available PLMNsdoes not include a PLMN that is also included in the Operator ControlledPLMN Selector list, then the UE 205 stops the procedure and may attemptto connect via untrusted non-3GPP access.

Moreover, the UE 205 selects the first S-NSSAI based on configurationinformation in the UE 205. For example, the UE 205 may be configured toprefer an S-NSSAI corresponding to a network slice suitable for massiveIoT communication (e.g. with a Slice/Service Type=3, as defined in TS23.501), or an S-NSSAI corresponding to a network slice suitable forultra-reliable and low-latency communication (e.g. with a Slice/ServiceType=2, as defined in TS 23.501). Note that the S-NSSAIs supported bythe first PLMN may be either provided in the PLMN list 724 (e.g.,received in messaging 722, step 4b).

In step 7, the UE 205 selects a non-3GPP access network (e.g. an SSID)to connect to (see block 732). Non-3GPP access network selection may beas follows:

The UE 205 puts the available non-3GPP access networks in priorityorder. In case of WLAN access, the UE 205 may construct this prioritizedlist by using the WLANSP rules (if provisioned), or any otherUE-implementation-specific means. Then, from the prioritized list ofnon-3GPP access networks, the UE 205 selects the highest prioritynon-3GPP access network that supports 5G connectivity-without-NAS to thefirst PLMN and with the first S-NSSAI.

In the example shown in FIG. 2, if the UE 205 selected PLMN-d in step 6,then the UE 205 would select the non-3GPP access network 2, if the UE205 was configured to prefer S-NSSAI-z over S-NSSAI-w. Alternatively,the UE 205 would select the non-3GPP access network 3, if the UE 205 wasconfigured to prefer S-NSSAI-w over S-NSSAI-z.

In Step 8, after the UE 205 completes the access network selectionprocedure, the UE 205 initiates the establishment of the desired dataconnection by sending a request message to the selected non-3GPP accessnetwork that contains the first PLMN and the first S-NSSAI (seemessaging 734). In various embodiments, the UE 205 sends a requestmessage to the selected SSID that contains the first PLMN and the firstS-NSSAI, wherein the request message is sent for establishing a dataconnection to a DN via the first PLMN and the first S-NSSAI. Note thatthe S-NSSAI is composed of a Slice/Service Type and an optional SliceDifferentiator. The first PLMN and the first S-NSSAI are contained inthe NAI provided by the UE 205, e.g.,“NAI=<username>@sdD16273.st03.snssai.mnc123.mcc45.3 gppnetwork.org” (seemessaging 734, step 8d). With this NAI, the UE 205 indicates it wants toconnect to the PLMN with MCC=45 and MNC=123, and it wants to use anetwork slice in the PLMN with Slice/Service Type=03 and SliceDifferentiator=D16273. In one example, the establishment procedure isinitiated by using the EAP protocol.

In Step 9, the TWAP 704 selects a TWIF 706 which supports the first PLMNand the first S-NSSAI provided by the UE 205 (see block 736). In thisstep the TWAP 704 utilizes the information received by one or more TWIFs(e.g., in messages 720).

In Step 10, the TWAP 704 sends an AAA Request message to the selectedTWIF 706 indicating that a UE 205 wants to establish a data connectionvia a 5G PLMN without using the NAS protocol (see messaging 738). TheTWIF 706 determines the first PLMN and the first S-NSSAI by examiningthe NAI provided by the UE 205 (see block 740).

In Step 11, the TWIF 706 selects an AMF (here, AMF 708) in the firstPLMN and sends a NAS message to the AMF 708 that includes the firstS-NSSAI and a PDU Session Establishment request (see messaging 742, step11a). This NAS message indicates that a new PDU Session is required fora UE that does not support NAS.

Subsequently, signaling takes place between the UE 205, the TWIF 706,the AMF 708, the AUSF 714 and other network functions in 5GC (e.g., PCF710 and UDM 712), which authenticates the UE 205 and establishes a PDUSession to be used by the UE 205 (see messaging 742, step 11b). Duringthis step, the UE 205 does not exchange any NAS messages, but ratherexchanges EAP messages, which are typically used for accessing anon-3GPP access network. Note that the AMF 708 may use the “default DNNfor delegated PDU session” received earlier to determine the DN (e.g.,for PDU session establishment).

In Step 12, the data connection (e.g., PDU Session) is finallyestablished connecting the UE 205 with a Data Network (e.g., DN 250),via the selected non-3GPP access network and the first S-NSSAI in thefirst PLMN (see block 744). A UPF 716 in the network slice in the firstPLMN that corresponds to the first S-NSSAI anchors the N3 tunnel. Theaccess network selection procedure 700 ends.

FIG. 8 depicts a method 800 for access network selection for UEs notsupporting NAS over non-3GPP access, according to embodiments of thedisclosure. In some embodiments, the method 800 is performed by anapparatus, such as the remote unit 105, the UE 205, and/or the userequipment apparatus 500. In certain embodiments, the method 800 may beperformed by a processor executing program code, for example, amicrocontroller, a microprocessor, a CPU, a GPU, an auxiliary processingunit, a FPGA, or the like.

The method 800 begins and creates 805 a first list of available PLMNs,each PLMN connectable via a non-3GPP access network without using a NASprotocol. The method 800 includes selecting 810 a first PLMN from thefirst list. Selecting 810 a first PLMN from the first list may be asdescribed above with reference to FIGS. 7A-7B.

The method 800 includes selecting 815 a first network slice supported bythe first PLMN. Here, the first network slice is identified by aS-NSSAI. Selecting 815 a first network slice supported by the first PLMNmay be as described above with reference to FIGS. 7A-7B.

The method 800 includes creating 820 a second list of available non-3GPPaccess networks. The method 800 includes selecting 825 a first non-3GPPaccess network from the second list. Selecting 825 a first non-3GPPaccess network from the second list may be as described above withreference to FIGS. 7A-7B.

The method 800 includes beginning 830 a connectivity procedure over thefirst non-3GPP access network. Here, the connectivity procedure createsa data connection for the apparatus via the first network slice in thefirst PLMN. Moreover, the connectivity procedure does not use the NASprotocol. The method 800 ends.

FIG. 9 depicts a method 900 for access network selection for UEs notsupporting NAS over non-3GPP access, according to embodiments of thedisclosure. In some embodiments, the method 900 is performed by anapparatus, such as the access point 131, the first TWAP 310, the secondTWAP 315, the first FN-RG 410, the second FN-RG 415, the networkequipment apparatus 600, and/or the TWAP 704. In certain embodiments,the method 900 may be performed by a processor executing program code,for example, a microcontroller, a microprocessor, a CPU, a GPU, anauxiliary processing unit, a FPGA, or the like.

The method 900 begins and receives 905 a set of PLMNs for whichconnectivity is supported without using a non-access stratum NASprotocol. The set of PLMNs is received from one or more interworkingfunctions that provide access to one or more PLMNs.

The method 900 includes, for each PLMN in the set, receiving 910 a listof one or more supported network slices, a network slice beingidentified by a S-NSSAI.

The method 900 includes, from a first remote unit, receiving 915 aconnection request message, the connection request message indicating afirst PLMN from the set and a first S-NS SAI.

The method 900 includes forwarding 920 the connection request message toa first interworking function. The method 900 ends.

Disclosed herein is a first apparatus for access network selection forUEs not supporting NAS over non-3GPP access. In various embodiments, thefirst apparatus may be a user terminal, such as the remote unit 105, theUE 205, and/or the user equipment apparatus 500. The first apparatusincludes a processor and a transceiver that communicates with one ormore non-3GPP access networks. The processor creates a first list ofavailable PLMNs, each PLMN connectable via a non-3GPP access networkwithout using a NAS protocol. The processor selects a first PLMN fromthe first list and selects a first network slice supported by the firstPLMN. Here, the first network slice is identified by a first S-NSSAI.The processor creates a second list of available non-3GPP accessnetworks and selects a first non-3GPP access network from the secondlist. The processor begins a connectivity procedure over the firstnon-3GPP access network. Here, the connectivity procedure creates a dataconnection for the apparatus via the first network slice in the firstPLMN. Moreover, the connectivity procedure does not use the NASprotocol.

In some embodiments, creating the first list of available PLMNs includesdiscovering a plurality of available non-3GPP access networks anddetermining, for each available non-3GPP access network, a set of PLMNswhich are connectable without using the NAS protocol and one or morenetwork slices supported by each PLMN in the set. In certainembodiments, determining the set of PLMNs which are connectable withoutusing the NAS protocol and the one or more network slices supported byeach PLMN in the set includes using an access network query protocol toacquire a list of PLMNs connectable via each available non-3GPP accessnetwork without using the NAS protocol and the network slices supportedfor each PLMN in the list of PLMNs connectable via each availablenon-3GPP access network without using the NAS protocol. In certainembodiments, the first non-3GPP access network is a highest priorityavailable non-3GPP access network that supports connectivity to thefirst network slice in the first PLMN.

In some embodiments, beginning the connectivity procedure over the firstnon-3GPP access network includes sending a request message to the firstnon-3GPP access network that indicates the first PLMN and the firstS-NSSAI. In certain embodiments, the request message includes NAIcontaining identifiers for the first PLMN and for the first S-NSSAI.

In some embodiments, creating the second list includes discovering aplurality of available non-3GPP access networks and ordering theplurality of available non-3GPP access networks into a prioritized listbased on a set of WLANSP rules. In such embodiments, the second list maybe ordered based on operating parameters of the plurality of availablenon-3GPP access networks.

In some embodiments of the first apparatus, the processor selects thefirst S-NSSAI using configuration information in the apparatus. Incertain embodiments, beginning the connectivity procedure includescreating a data connection via the first network slice in the first PLMNand via one of: a TWIF in the first non-3GPP access network, and a FN-RGin the first non-3GPP access network.

Disclosed herein is a first method for access network selection for UEsnot supporting NAS over non-3GPP access. In various embodiments, thefirst method may be implemented by a user terminal, such as the remoteunit 105, the UE 205, and/or the user equipment apparatus 500. The firstmethod includes creating a first list of available PLMNs, each PLMNconnectable via a non-3GPP access network without using a NAS protocol.The first method includes selecting a first PLMN from the first list andselecting a first network slice supported by the first PLMN. Here, thefirst network slice is identified by a S-NSSAI. The first methodincludes creating a second list of available non-3GPP access networksand selecting a first non-3GPP access network from the second list. Thefirst method includes beginning a connectivity procedure over the firstnon-3GPP access network. Here, the connectivity procedure creates a dataconnection for the apparatus via the first network slice in the firstPLMN. Moreover, the connectivity procedure does not use the NASprotocol.

In some embodiments of the first method, creating the first listincludes discovering a plurality of available non-3GPP access networksand determining, for each available non-3GPP access network, a set ofPLMNs which are connectable without using the NAS protocol and one ormore network slices supported by each PLMN in the set. In certainembodiments, the first non-3GPP access network is a highest priorityavailable non-3GPP access network that supports connectivity to thefirst network slice in the first PLMN. In certain embodiments,determining the set of PLMNs which are connectable without using the NASprotocol and the one or more network slices supported by each PLMN inthe set includes using an access network query protocol to acquire alist of PLMNs connectable via each available non-3GPP access networkwithout using the NAS protocol and the network slices supported for eachPLMN in the list of PLMNs connectable via each available non-3GPP accessnetwork without using the NAS protocol.

In certain embodiments of the first method, beginning the connectivityprocedure over the first non-3GPP access network includes sending arequest message to the first non-3GPP access network that indicates thefirst PLMN and the first S-NSSAI. In certain embodiments, the requestmessage includes a NAI containing identifiers for the first PLMN and forthe first S-NSSAI. In some embodiments of the first method, creating thesecond list includes discovering a plurality of available non-3GPPaccess networks and ordering the plurality of available non-3GPP accessnetworks into a prioritized list based on a set of WLANSP rules. In suchembodiments, the second list may be ordered based on operatingparameters of the plurality of available non-3GPP access networks.

In some embodiments of the first method, selecting the first S-NSSAI isbased on configuration information in the apparatus. In some embodimentsof the first method, beginning the connectivity procedure includescreating a data connection via the first network slice in the first PLMNvia one of: a TWIF in the first non-3GPP access network, and a FN-RG inthe first non-3GPP access network.

Disclosed herein is a second apparatus for access network selection forUEs not supporting NAS over non-3GPP access. In various embodiments, thesecond apparatus may be an access point of a non-3GPP access network,such as the access point 131, the first TWAP 310, the second TWAP 315,the first FN-RG 410, the second FN-RG 415, the network equipmentapparatus 600, and/or the TWAP 704. The second apparatus includes aprocessor and a transceiver that communicates with one or more remoteunits and with one or more interworking functions that provide access toone or more PLMNs. The processor receives, from one or more interworkingfunctions, a set of PLMNs for which connectivity is supported withoutusing a NAS protocol.

The processor receives, for each PLMN in the set, a list of one or moresupported network slices, a network slice being identified by a S-NSSAI.The processor receives, from a first remote unit, a connection requestmessage, the connection request message indicating a first PLMN from theset and a first S-NSSAI. The processor forwards the connection requestmessage to a first interworking function.

In some embodiments, the processor further selects the firstinterworking function based on the first PLMN and the first S-NSSAI. Incertain embodiments, the connection request message includes a NAIcontaining identifiers for the first PLMN and for the first S-NSSAI.

Disclosed herein is a second method for access network selection for UEsnot supporting NAS over non-3GPP access. In various embodiments, thesecond method may be implemented by an access point of a non-3GPP accessnetwork, such as the access point 131, the first TWAP 310, the secondTWAP 315, the first FN-RG 410, the second FN-RG 415, the networkequipment apparatus 600, and/or the TWAP 704. The second method includesreceiving, from one or more interworking functions, a set of PLMNs forwhich connectivity is supported without using a non-access stratum NASprotocol. Here, the one or more interworking functions provide access toone or more PLMNs.

The second method includes receiving, for each PLMN in the set, a listof one or more supported network slices, a network slice beingidentified by a S-NSSAI. The second method includes receiving, from afirst remote unit, a connection request message, the connection requestmessage indicating a first PLMN from the set and a first S-NSSAI. Thesecond method includes forwarding the connection request message to afirst interworking function.

In some embodiments, the second method further includes selecting thefirst interworking function based on the first PLMN and the firstS-NSSAI. In certain embodiments, the connection request message includesa NAI containing identifiers for the first PLMN and for the firstS-NSSAI.

Embodiments may be practiced in other specific forms. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

1. An apparatus comprising: a transceiver that communicates with one ormore non-3GPP access networks; and a processor that: creates a firstlist of available public land mobile networks (“PLMNs”), each PLMNconnectable via a non-3GPP access network using a 5G connectivitywithout non-access stratum (“NAS”); selects a first PLMN from the firstlist; creates a second list of available non-3GPP access networks;selects a first non-3GPP access network from the second list; and beginsa connectivity procedure over the first non-3GPP access network, whereinthe connectivity procedure creates a data connection for the apparatusvia the first PLMN, and wherein the connectivity procedure does not usethe NAS protocol.
 2. The apparatus of claim 1, wherein creating thefirst list of available PLMNs comprises: discovering a plurality ofavailable non-3GPP access networks; and determining, for each availablenon-3GPP access network, a set of PLMNs which are connectable using a 5Gconnectivity without NAS protocol and one or more network slicessupported by each PLMN in the set.
 3. The apparatus of claim 2, whereindetermining the set of PLMNs which are connectable using a 5Gconnectivity without NAS comprises using an access network queryprotocol (“ANQP”) to acquire a list of PLMNs connectable via eachavailable non-3GPP access network using a 5G connectivity without NAS.4. The apparatus of claim 2, wherein the first non-3GPP access networkis a highest priority available non-3GPP access network that supportsconnectivity to the first PLMN.
 5. The apparatus of claim 1, whereinbeginning the connectivity procedure over the first non-3GPP accessnetwork comprises sending a request message to the first non-3GPP accessnetwork comprising a network access identifier (“NAI”), the NAIcontaining an identifier for the first PLMN.
 6. The apparatus of claim5, wherein the NAI contains also an identifier for a first SingleNetwork Slice Selection Assistance Information (“S-NSSAI”) and whereinthe connectivity procedure creates a data connection for the apparatusvia the first S-NSSAI in the first PLMN.
 7. The apparatus of claim 1,wherein creating the second list comprises: discovering a plurality ofavailable non-3GPP access networks; and ordering the plurality ofavailable non-3GPP access networks into a prioritized list based on aset of wireless local area network selection policy (“WLANSP”) rules. 8.The apparatus of claim 7, wherein the second list is ordered based onoperating parameters of the plurality of available non-3GPP accessnetworks.
 9. (canceled)
 10. The apparatus of claim 1, wherein beginningthe connectivity procedure comprises creating a data connection via thefirst PLMN and via one of: a trusted wireless local area networkinterworking function (“TWIF”) in the first non-3GPP access network, anda fixed network residential gateway (“FN-RG”) in the first non-3GPPaccess network.
 11. A method comprising: creating, at a remote unit, afirst list of available public land mobile networks (“PLMNs”), each PLMNconnectable via a non-3GPP access network using a 5G connectivitywithout non-access stratum (“NAS”); selecting, by the remote unit, afirst PLMN from the first list; creating, at a remote unit, a secondlist of available non-3GPP access networks; selecting, by the remoteunit, a first non-3GPP access network from the second list; andbeginning, by the remote unit, a connectivity procedure over the firstnon-3GPP access network, wherein the connectivity procedure creates adata connection for the remote unit via the first PLMN, and wherein theconnectivity procedure does not use the NAS protocol.
 12. The method ofclaim 11, wherein creating the first list comprises: discovering aplurality of available non-3GPP access networks; determining, for eachavailable non-3GPP access network, a set of PLMNs which are connectableusing a 5G connectivity without NAS.
 13. The method of claim 12, whereindetermining the set of PLMNs which are connectable using a 5Gconnectivity without NAS comprises using an access network queryprotocol (“ANQP”) to acquire a list of PLMNs connectable via eachavailable non-3GPP access network using a 5G connectivity without NAS.14. The method of claim 12, wherein the first non-3GPP access network isa highest priority available non-3GPP access network that supportsconnectivity to the first PLMN.
 15. The method of claim 11, whereinbeginning the connectivity procedure over the first non-3GPP accessnetwork comprises sending a request message to the first non-3GPP accessnetwork comprising a network access identifier (“NAI”), the NAIcontaining an identifier for the first PLMN.
 16. The method of claim 15,wherein the NAI contains also an identifier for a first Single NetworkSlice Selection Assistance Information (“S-NSSAI”) and wherein theconnectivity procedure creates a data connection for the apparatus viathe first S-NSSAI in the first PLMN.
 17. The method of claim 11, whereincreating the second list comprises: discovering a plurality of availablenon-3GPP access networks; and ordering the plurality of availablenon-3GPP access networks into a prioritized list based on a set ofwireless local area network selection policy (“WLANSP”) rules.
 18. Themethod of claim 17, wherein the second list is ordered based onoperating parameters of the plurality of available non-3GPP accessnetworks.
 19. (canceled)
 20. The method of claim 11, wherein beginningthe connectivity procedure comprises creating a data connection via thefirst PLMN via one of: a trusted wireless local area networkinterworking function (“TWIF”) in the first non-3GPP access network, anda fixed network residential gateway (“FN-RG”) in the first non-3GPPaccess network.
 21. (canceled)
 22. (canceled)
 23. (canceled) 24.(canceled)
 25. (canceled)
 26. (canceled)